Why is the bot not responding to text messages?

Question

Bots

import telebot
import config

from telebot import types

bot = telebot.TeleBot(config.TOKEN)

@bot.message_handler(commands=['start'])
def start(message):

# keyboard
markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard =True)
item_social = types.KeyboardButton('Social Studies')
item_history = types.KeyboardButton('History')
item_literature = types.KeyboardButton('Literature')
item_russian = types.KeyboardButton('Russian')

markup.add(item_social, item_history, item_literature, item_russian)

# welcome message and keyboard output
bot.send_message(message.chat.id, ' Greetings! I'm your future school assistant bot AK nerd bot! ', reply_markup=markup)

# checking which subject is selected
@bot.message_handler(content_types=['text'])
def wichsubject(message):
if message.chat.type == 'private':
#DORM
if message.text == 'Socio':

markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard=True)
back = types.KeyboardButton( 'Back')
item_term1 = types.KeyboardButton('Absenteeism')
markup.add(back, item_term1)

bot.send_message(message.chat.id, 'You can enter a Social Studies term that interests you.', reply_markup=markup )

@bot.message_handler(content_types=['text'])
def send_infosocial(message):
if message.text == 'Absenteeism':
bot.send_message(message.chat.id, 'In constitutional law, a term for the voluntary non-participation of voters in an election or referendum vote.', reply_markup=markup)
else:
bot.send_message(message.chat.id, 'I don't know yet', reply_markup=markup) #HISTORY

elif
message.text == 'History':
markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard=True)
back = types.KeyboardButton('Back')
markup.add(back)

bot.send_message(message.chat.id, 'You can enter the historical event date or term you are interested in.', reply_markup=markup)

@bot.message_handler(content_types=['text'])
def send_infohistory(message):
if message .text == '1941':
bot.send_message(message.chat.id, 'World War II.', reply_markup=markup)

elif '1861' in message.text.lower():
bot.send_message(message.chat. id, 'Abolition of serfdom', reply_markup=markup)

else:
bot.send_message(message.chat.id, 'I don't know yet', reply_markup=markup)


# LITERATURE
elif message.text == 'Literature':
markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard=True)
back = types.KeyboardButton('Back')
markup.add(back)


bot.send_message(message.chat.id, 'You can enter the name of the work without quotes, and I will try to show a brief information about it.', reply_markup=markup)

# RUSSIAN
elif message.text == 'Russian':
markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard=True)
back = types.KeyboardButton('Back')
markup.add(back)
bot.send_message(message.chat .id, 'You can enter the rule you are interested in, and I will try to define it.', reply_markup=markup)



# If the Back Button is selected
elif message.text == 'Back':
# keyboard
markup = types.ReplyKeyboardMarkup(resize_keyboard=True, one_time_keyboard=True)
item_social = types.KeyboardButton('Social Studies')
item_history = types.KeyboardButton('History')
item_literature = types.KeyboardButton('Literature')
item_russian = types.KeyboardButton( 'Russian language')

markup.add(item_social, item_history, item_literature, item_russian)

bot.send_message(message.chat.id, 'Select the subject you want to learn', reply_markup=markup)



# RUN
while True:
try:
bot.polling (none_stop=True)

except Exception as e:
print(e)

time.sleep(15)